1. Field of the Invention
The present invention relates to a water-soluble extract of asiaticoside and madecassoside from Centella asiatica, which is able to protect liver cells with an anti-fibrosis effect, and to an isolating method thereof.
2. Description of the Prior Art
Centella asiatica (L.) Urb, a family of umbelliferea which is autogenous in Madagascar island of Africa and India, has been used for the treatment of a local wound since a long time ago (Poizot. A., Dumez. D, C.R. Acad. Sci [D] 286, 1978). Many researchers report that the titrated extract of Centella asiatica (hereinafter referred to as xe2x80x9cTECAxe2x80x9d) is effective to a local injury of the tissues. In fact, TECA is acknowledged as a medicinal effector and commercially available under the tradename of xe2x80x9cMadecassolxe2x80x9d (asiaticoside:asiatic acid:madecassic acid=4:3:3). Its medicinal effect is to restore a damaged tissue to a nearly original state by modifying the fibrosis progress with protection of the cells in the tissue.
These components, however, are limited to the curing of surgical wounds and their extraction, as disclosed in Korean Pat. Publication Nos. 87-1458, 87-1573 and 91-2518, requires elaborate processes, so that the yield and purity thereof is poor. In addition, the objective main components are genin (asiatic acid, madecassic acid and madasiatic acid) and asiaticoside, which are both water-insoluble so that there is a limit in expanding their uses.
Although the pre-existing TECA exhibits an excellent effect of anti-fibrosis, its physical property of water insolubility forces itself to be in the form of powder, limiting its application range to the curing of surgical wound.
Intensive research repeated by the present inventors aiming to expand the pharmaceutical use of TECA, resulted in the finding that a treatment of Centella asiatica with an aqueous alcohol greatly helps extract the components which are soluble in water and effective in the protection and the anti- fibrosis of liver cells.
Therefore, it is an object of the present invention to provide a water-soluble extract of asiaticoside and madecassoside from Centella asiatica, which shows an excellent effect of the protection and the anti-fibrosis of liver cells.
It is another object of the present invention to provide an isolating method of the water-soluble extract.
In accordance with an aspect of the present invention, there is provided a method for isolating a water-soluble extract of asiaticoside and madecassoside from Centella asiatica, comprising the steps of: subjecting an aqueous alcohol containing Centella asiatica to cold-precipitation; treating the extract in the aqueous alcohol with a halogenide solvent for layer separation; extracting the aqueous layer with a higher alcohol; washing the extract in the alcohol layer with sodium hydroxide, then with water and concentrating the extract; crystallizing the extract with ethyl acetate, to give a crystal; and washing the crystal.
In accordance with another aspect of the present invention, there is provided a water-soluble extract of asiaticoside and madecassoside from Centella asiatica, which is able to protect liver cells with an anti-fibrosis effect.